Covalent Immobilization of β-Glucosidase on Magnetic Particles for Lignocellulose Hydrolysis

• Published in: Applied biochemistry and biotechnology 2013-04, Vol.169 (7), p.2076-2087
• Main Authors: Alftrén, Johan, Hobley, Timothy John
• Format: Article
• Language: English
• Subjects: beta-Glucosidase - metabolism; Biochemistry; Biological and medical sciences; Biotechnology; Chemistry; Chemistry and Materials Science; Enzyme Stability; Enzymes, Immobilized - chemistry; Enzymes, Immobilized - metabolism; Fundamental and applied biological sciences. Psychology; General aspects; Glutaral - analogs & derivatives; Glutaral - chemistry; Hydrolysis; Immobilization techniques; Lignin - metabolism; Magnetics; Methods. Procedures. Technologies; Triazines - chemistry
• ISSN: 0273-2289; 1559-0291
• DOI: 10.1007/s12010-013-0122-5

β-Glucosidase hydrolyzes cellobiose to glucose and is an important enzyme in the consortium used for hydrolysis of cellulosic and lignocellulosic feedstocks. In the present work, β-glucosidase was covalently immobilized on non-porous magnetic particles to enable re-use of the enzyme. It was found that particles activated with cyanuric chloride and polyglutaraldehyde gave the highest bead-related immobilized enzyme activity when tested with p -nitrophenyl-β-D-glucopyranoside (104.7 and 82.2 U/g particles, respectively). Furthermore, the purified β-glucosidase preparation from Megazyme gave higher bead-related enzyme activities compared to Novozym 188 (79.0 and 9.8 U/g particles, respectively). A significant improvement in thermal stability was observed for immobilized enzyme compared to free enzyme; after 5 h (at 65 °C), 36 % of activity remained for the former, while there was no activity in the latter. The performance and recyclability of immobilized β-glucosidase on more complex substrate (pretreated spruce) was also studied. It was shown that adding immobilized β-glucosidase (16 U/g dry matter) to free cellulases (8 FPU/g dry matter) increased the hydrolysis yield of pretreated spruce from ca. 44 % to ca. 65 %. In addition, it was possible to re-use the immobilized β-glucosidase in the spruce and retain activity for at least four cycles. The immobilized enzyme thus shows promise for lignocellulose hydrolysis.